So on Sunday’s Meet The Press, Cory Booker made some news. He criticized the Obama administration for running ads questioning Mitt Romney’s connection to Bain and Romney’s claims of being a job creator. Booker called the ads “nauseating.”

Needless to say Booker – a Democratic Mayor from Newark New Jersey – received a huge amount of backlash from the social media and other prominent Democrats, causing him to later release a web video praising President Obama and expressing his everlasting love and support of the President.

But it was too late, the damage was already done.

And now we’re starting to see why this very popular Democratic Mayor spoke up against the Obama administration and in defense to the Romney campaign. Thanks to some investigative work by Think Progress, it seems that Romney’s Bain was a huge donor to the Booker 2002 campaign.

A ThinkProgress examination of New Jersey campaign finance records for Booker’s first run for Mayor — back in 2002 — suggests a possible reason for his unease with attacks on Bain Capital and venture capital. They were among his earliest and most generous backers.

Contributions to his 2002 campaign from venture capitalists, investors, and big Wall Street bankers brought him more than $115,000 for his 2002 campaign. Among those contributing to his campaign were John Connaughton ($2,000), Steve Pagliuca ($2,200), Jonathan Lavine ($1,000) — all of Bain Capital. While the forms are not totally clear, it appears the campaign raised less than $800,000 total, making this a significant percentage.

He and his slate also jointly raised funds for the “Booker Team for Newark” joint committee. They received more than $450,000 for the 2002 campaign from the sector — including a pair of $15,400 contributions from Bain Capital Managing Directors Joshua Bekenstein and Mark Nunnelly. It appears that for the initial campaign and runoff, the slate raised less than $4 million — again making this a sizable chunk.